Lichenoid and interface dermatoses

Vulvar Lichenoid Dermatoses With Emphasis on the Distinction Between Lichen Sclerosus and Lichen Planus: A 10-Year Study

OBJECTIVES

Lichen planus (LP) and lichen sclerosus (LS) are the most common vulvar lichenoid dermatoses. The diagnostic challenges are due to site-specific variation in microscopic appearance and small-sized biopsies. Authentication of diagnostic criteria to distinguish LS and LP to uncover any resemblance or divergence in presentation of these conditions is attempted.

METHODS

Cases of vulvar LP and LS diagnosed between January 2012 to December 2022 were included. The clinical details included age, presenting symptoms, examination findings, and other organ involvement. Histopathological analysis of epidermal, dermal, and adnexal findings was done.

RESULTS

There were 28 cases of vulvar LP and 72 cases of LS, with a median age of 51 and 60 years, respectively. Depigmentation and atrophy were the major clinical features in LS, whereas ulcers/erosions and erythema were more prevalent in LP with a significantly higher incidence of oral involvement. The most diagnostic feature in LS was diffuse dermal sclerosis (76.8%) and interstitial pattern of inflammation (81.4%), whereas the characteristic features in LP cases was a lichenoid pattern of inflammation (85.7%), necrotic keratinocytes, and lymphocytic exocytosis. In 44.4% of LS, unconventional features like compact orthokeratosis, parakeratosis, thickened/wedge-shaped hypergranulosis, and sawtooth rete pegs were noted. Lichen sclerosus with lichenoid inflammation (21.4%) mimicked LP, from which it was distinguished by presence of thickened or diminished granular layer with basal melanin absence (60%) and dermal homogenization (80%).

CONCLUSION

Although the classical, well-established variant of LS poses no diagnostic difficulty, the unconventional variant may mimic LP. Identification of the subtle histological clues demonstrated in this study can help to arrive at the correct diagnosis.

HIV-associated photodermatitis in African populations

Photosensitive dermatoses are seen in 5% of HIV-infected persons. These include drug- and chemical-induced photoallergic and phototoxic reactions, chronic actinic dermatitis of HIV, photo lichenoid drug eruptions, and porphyria. Data on photodermatitis in HIV are limited to case reports and series. The pathogenesis is not completely understood and includes a th2 phenotype in HIV which results in impaired barrier function and resultant allergen sensitisation as well as immune dysregulation. The objective of this manuscript is to review the literature on the clinical phenotype, pathogenesis, role of photo and patch testing, outcomes, and treatment of photodermatitis in HIV in an African population.

A Case of Multiple Necrotic Dyskeratotic Cells within the Upper Epidermis and Horny Layer Revealing Persistent Papules and Plaques of Adult-Onset Still's Disease

It is important to differentiate violaceous to dusky red papules and plaques that widely persist on the trunk and extremities because there are dermatoses that could be fatal, such as lupus erythematosus, dermatomyositis, drug eruptions, and graft-versus-host disease. Dyskeratotic cells only in the upper epidermis and horny layer are not well known, but it is a distinctive histopathological pattern of atypical type of rash of adult-onset Still's disease (AOSD). AOSD rash is a transient salmon-colored rash that occurs and disappears with fever; however, an atypical type of rash called "persistent dermal plaque" or "persistent pruritic eruptions" has also been reported. It occurs and persists even after fever subsides. Herein, we describe a case with necrotic dyskeratotic cells in the upper epidermis and horny layer without AOSD symptoms lasting for five years.

[Esophageal Lichen Planus - An Underdiagnosed Disease]

An involvement of the esophagus in patients with lichen planus was described for the first time in 1982. Ever since, it has been seen as a rarity. However, studies over the last 10 years have shown a higher prevalence than expected. It may even be supposed that esophageal lichen planus (ELP) is more common than eosinophilic esophagitis. ELP mostly affects middleaged women. The principal symptom is dysphagia. Endoscopically, ELP is characterized by denudation and tearing of the mucosa, trachealization and hyperkeratosis and esophageal stenosis may occur in patients with long courses of the disease. Histologic findings including mucosal detachment, T-lymphocytic infiltrate, intraepithelial apoptosis (civatte bodies) and dyskeratosis are crucial. Direct immunofluorescence shows fibrinogen deposits along the basement membrane zone. So far, there is no well-established therapy but a treatment with topic steroids is effective in 2/3 of the patients. Common therapy of lichen planus of the skin seems to be ineffective for treatment of ELP. Symptomatic esophageal stenosis should be endoscopically dilated. ELP joins the group of "new" immunologic diseases of the esophagus.

Der Lichen planus des Ösophagus – Eine unterschätzte Erkrankung

Eine Beteiligung des Ösophagus bei der Hauterkrankung Lichen planus wurde erstmals 1982 beschrieben und fast 30 Jahre lang als eine Rarität angesehen. Untersuchungen der letzten 10 Jahre aber zeigen, dass diese Erkrankung weniger selten ist als angenommen. Es ist sogar anzunehmen, dass der ösophageale Lichen planus (Esophageal Lichen planus, ELP) häufiger ist als die Eosinophile Ösophagitis (EoE). Die Ösophagusbeteiligung betrifft meist Frauen im mittleren Alter. Das Hauptsymptom ist eine Dysphagie. Endoskopisch erkennt man in der Speiseröhre eine charakteristische Schleimhautablösung, eine Trachealisierung, und gelegentlich Hyperkeratosen und bei langem Bestehen auch Stenosen. Wegweisend ist die Histologie mit einer subepithelialen Ablösung sowie einem bandförmigen Infiltrat aus T-Lymphozyten, dem Nachweis von apoptotischen Keratinozyten (Civatte Bodies) und Dyskeratosen. Die direkte Immunfluoreszenz zeigt Fibrinogen-Ablagerungen entlang der Basalmembran. Eine etablierte Therapie gibt es bisher nicht. Die Behandlung mit topischen Steroiden ist in ⅔ der Fälle wirksam. Eine Therapie wie beim klassischen Lichen planus scheint unwirksam zu sein. Bei symptomatischen Stenosen kann eine Dilatation indiziert sein. Der ELP reiht sich in die Gruppe der „neuen“ immunologisch vermittelten Erkrankungen des Ösophagus ein.

Esophageal lichen planus: Current knowledge, challenges and future perspectives

Lichen planus (LP) is a frequent, chronic inflammatory disease involving the skin, mucous membranes and/or skin appendages. Esophageal involvement in lichen planus (ELP) is a clinically important albeit underdiagnosed inflammatory condition. This narrative review aims to give an overview of the current knowledge on ELP, its prevalence, pathogenesis, clinical manifestation, diagnostic criteria, and therapeutic options in order to provide support in clinical management. Studies on ELP were collected using PubMed/Medline. Relevant clinical and therapeutical characteristics from published patient cohorts including our own cohort were extracted and summarized. ELP mainly affects middle-aged women. The principal symptom is dysphagia. However, asymptomatic cases despite progressed macroscopic esophageal lesions may occur. The pathogenesis is unknown, however an immune-mediated mechanism is probable. Endoscopically, ELP is characterized by mucosal denudation and tearing, trachealization, and hyperkeratosis. Scarring esophageal stenosis may occur in chronic courses. Histologic findings include mucosal detachment, T-lymphocytic infiltrations, epithelial apoptosis (Civatte bodies), dyskeratosis, and hyperkeratosis. Direct immuno-fluorescence shows fibrinogen deposits along the basement membrane zone. To date, there is no established therapy. However, treatment with topical steroids induces symptomatic and histologic improvement in two thirds of ELP patients in general. More severe cases may require therapy with immunosuppressors. In symptomatic esophageal stenosis, endoscopic dilation may be necessary. ELP may be regarded as a precancerous condition as transition to squamous cell carcinoma has been documented in literature. ELP is an underdiagnosed yet clinically important differential diagnosis for patients with unclear dysphagia or esophagitis. Timely diagnosis and therapy might prevent potential sequelae such as esophageal stenosis or development of invasive squamous cell carcinoma. Further studies are needed to gain more knowledge about the pathogenesis and treatment options.

Annular lichenoid diseases

Annular lichenoid diseases encompass a diverse range of pathologies that present as circular, raised, or flat lesions that may vary in size and number. Examples include annular lichenoid dermatitis of youth, annular lichen planus, erythema dyschromicum perstans, erythema multiforme, fixed drug eruption, lichen sclerosus, neonatal lupus, porokeratosis, subacute cutaneous lupus erythematosus, and lichenoid syphilis. Clinical morphology and histopathology can differentiate these entities.

Histology of Skin Alterations in Lupus Erythematosus

Lupus erythematosus is an autoimmune connective tissue disorder showing a broad spectrum of clinical manifestations.

The aim of this study was to assess the correlation of skin histology and different types of lupus erythematosus.

Materials and methods: Fifty-one skin specimens were assessed from 39 female and 12 male patients with acute, subcutaneous and chronic lupus erythematosus, diagnosed and treated in the Department of Dermatology and Venereology, Alexandrovska University Hospital for a 4-year period.

Results: Follicular hyperkeratosis, epidermal atrophy, vacuolar degeneration and interface dermatitis were the most frequently observed lesions in chronic cutaneous lupus erythematosus while diffuse hyperkeratosis, epidermal atrophy and indistinct interface dermatitis in the dermis were predominant in subacute cutaneous lupus erythematosus. Lupus tumidus, a rare intermittent variant of cutaneous lupus erythematosus, showed almost no epidermal involvement and mucin deposition in the dermis. However, in one of our lupus tumidus patients the disease progressed to a systemic form with histological changes of acute cutaneous lupus erythematosus including atrophy, dermal-epidermal smoothing and lymphocytic infiltration in the dermis. Of note, a few patients showed histological changes of urticarial vasculitis-like and rheumatic-like patterns.

Conclusion: The correlation of clinical course, histopathological findings and immunological tests are of vital importance for the correct diagnosis and follow up of patients with lupus erythematodes, thus preventing complications and improving their quality of life.

[Esophageal Lichen Planus - an Underdiagnosed Disease]

An involvement of the esophagus in patients with lichen planus was described for the first time in 1982. Ever since, it has been seen as a rarity. However, studies over the last 10 years have shown a higher prevalence than expected. It may even be supposed that esophageal lichen planus (ELP) is more common than eosinophilic esophagitis. ELP mostly affects middle-aged women. The principal symptom is dysphagia. Endoscopically, ELP is characterized by denudation and tearing of the mucosa, trachealization and hyperkeratosis and esophageal stenosis may occur in patients with long courses of the disease. Histologic findings including mucosal detachment, T-lymphocytic infiltrate, intraepithelial apoptosis (civatte bodies) and dyskeratosis are crucial. Direct immunofluorescence shows fibrinogen deposits along the basement membrane zone. So far, there is no well-established therapy but a treatment with topic steroids is effective in 2/3 of the patients. Common therapy of lichen planus of the skin seems to be ineffective for treatment of ELP. Symptomatic esophageal stenosis should be endoscopically dilated. ELP joins the group of "new" immunologic diseases of the esophagus.

Lichenoid dermatoses involving the vulva: A clinical-pathologic correlation✰

The lichenoid tissue reaction pattern generally signifies cytotoxic damage to the epithelium. When such reaction pattern occurs on vulvar skin or mucosa, the effects can result in considerable morbidity. None of the entities discussed in this review are entirely unique to the vulva, however, some entities may classically occur at this site, while others tend to be widespread diseases that may incidentally affect vulvar skin and mucosa. Given the complex anatomy of the vulva and the bridging of a site showing both keratinizing squamous epithelium and non-keratinizing squamous mucosa, histopathologic features may display variation in presentation. Although identification of a "lichenoid reaction pattern" alone may provide insight into the disease process, understanding of clinical presentation and specific sites of involvement, along with recognition of the nuanced features of the disease entities can help establish a specific diagnosis. Accurate histopathologic diagnoses by pathologists can improve the ability for treating clinicians to implement timely and effective treatment.

The new differential diagnostic test for the lichenoid drug eruption

The differential diagnosis between lichenoid drug eruption (LDE) and lichen planus (LP) is difficult due to similar clinical and histological signs but important for treatment and prognosis. The purpose of this study was to propose the new diagnosis method for differentiate LDE from LP. During 2015-2018, 20 patients with confirmed LDE, 13 patients with LP and 134 controls were examined and treated at the Lenoblcenter. All enrolled patients were underwent the injection of 0.5 mL of the 2% lidocaine solution by insulin syringe into the papule with following histological examination. The formation of a blister (bulla) at the site of injection was considered a positive test result. Among LDE, 18 of 20 patients were found positive for developing blister (bulla) and two results were questionable. In 12 of 13 LP patents, bulla on the site of injection was not identified and the result of one patient was nonspecific. All control patients were negative for the proposed test. The histological sections showed that the bulla has corresponded to the separation of the epidermis from the dermis. Intracutaneous injection of 0.5 mL of lidocaine into the papule is an easy highly specific and sensitive method to differentiate LDE from LP.

A Systematic Approach to the Cutaneous Lymphoid Infiltrates: A Clinical, Morphologic, and Immunophenotypic Evaluation

CONTEXT.—

The evaluation of cutaneous lymphoid infiltrates, both neoplastic and inflammatory, occurs very frequently in routine dermatopathologic examination and consultation practices. The "tough" cutaneous lymphoid infiltrate is feared by many pathologists; skin biopsies are relatively small, whereas diagnostic possibilities are relatively broad. It is true that cutaneous lymphomas can be difficult to diagnose and that in many circumstances multiple biopsies are required to establish a correct diagnostic interpretation. As a reminder, one should understand that low-grade cutaneous lymphomas are indolent disorders that usually linger for decades and that therapy does not result in disease cure. It is also important to remember that in most circumstances, those patients will die from another process that is completely unrelated to a diagnosis of skin lymphoma (even in the absence of specific therapy).

OBJECTIVE.—

To use a clinicopathologic, immunophenotypic, and molecular approach in the evaluation of common lymphocytic infiltrates.

DATA SOURCES.—

An in-depth analysis of updated literature in the field of cutaneous lymphomas was done, with particular emphasis on updated terminology from the most recent World Health Organization classification of skin and hematologic tumors.

CONCLUSIONS.—

A diagnosis of cutaneous lymphoid infiltrates can be adequately approached using a systematic scheme following the proposed ABCDE system. Overall, cutaneous T- and B-cell lymphomas are rare and "reactive" infiltrates are more common. Evaluation of lymphoid proliferations should start with a good sense of knowledge of the clinical presentation of the lesions, the clinical differential considerations, and a conscientious and appropriate use of immunohistochemistry and molecular tools.

Esophageal lichen planus: towards diagnosis of an underdiagnosed disease

Background: Although lichen planus (LP) is a common skin disorder, the prevalence of esophageal involvement (ELP) and its clinical manifestations are poorly defined. We aimed to establish diagnostic criteria and characterize disease outcomes of ELP.Methods: Clinical, endoscopic, histological, and immunofluorescence data from consecutive patients with known LP between 2013 and 2018 were analyzed. We established endoscopic (denudation and tearing of the mucosa, hyperkeratosis and trachealization) and histological criteria (mucosal detachment, T-lymphocytic infiltrate, intraepithelial apoptosis, dyskeratosis, and fibrinogen deposits along the basement membrane) to grade disease severity. Endoscopic findings were correlated with clinical symptoms. Response to medical therapy was monitored.Results: Fifty-two consecutive patients (median age 59.5 years) were analyzed. According to our grading system, 16 patients were considered as severe and 18 as mild ELP. Dysphagia was the only symptom which differentiated patients with severe (14/16) or mild ELP (8/18) from patients without ELP (1/18). Concomitant oral and genital involvement of LP was associated with the presence of ELP, while oral involvement alone was not. Follow-up of 14/16 patients with severe EPL for at least one year revealed that most of these patients responded to topical corticosteroids (budesonide: n = 9/10 or fluticasone n = 2/2). Three budesonide patients experienced a resolution of symptomatic esophageal stenosis.Conclusions: Esophageal involvement of LP is frequent, but may be asymptomatic. ELP can be diagnosed using the diagnostic criteria proposed here. Dysphagia and combined oral and genital manifestation are associated with ELP. Therapy with topical corticosteroids appears to be a prudent therapeutic approach for ELP.

Lichen Planus Pemphigoides: From Lichenoid Inflammation to Autoantibody-Mediated Blistering

Lichen planus pemphigoides (LPP) is a very rare autoimmune sub-epidermal blistering disease associated with lichenoid skin changes. Initially thought to be a mere variant of more common inflammatory dermatoses, particularly Bullous Pemphigoid (BP) or Lichen Planus (LP), a growing body of evidence suggests that it is a disease entity in its own right. In common with a range of autoimmune blistering diseases, including BP, pemphigoid gestationis (PG), mucous membrane pemphigoid (MMP) and linear IgA dermatosis (LAD), a key feature of the disease is the development of autoantibodies against type XVII collagen (COL17). However, accurately establishing the diagnosis is dependent on a careful correlation between the clinical, histological and immunological features of the disease. Therefore, we present an up to date summary of the epidemiology and etiopathogenesis of LPP, before illustrating the predisposing and precipitating factors implicated in the development of the disease. In addition to a selective literature search, we compare reports of potential drug-induced cases of LPP with pharmacovigilance data available via OpenVigil. We subsequently outline the cardinal clinical features, important differential diagnoses and current treatment options. We conclude by demonstrating that an improved understanding of LPP may not only lead to the development of novel treatment strategies for the disease itself, but may also shed new light on the pathophysiology of more common and treatment-refractory autoimmune blistering diseases.

Histopathological diagnosis of persistent pruritic eruptions associated with adult-onset Still's disease

AIMS

Persistent pruritic eruptions (PPEs), presenting with dyskeratotic keratinocytes histologically, are characteristic skin rash in patients with adult-onset Still's disease (AOSD). The lesions may be histologically similar to other entities that present with dyskeratosis. In the present study, we compared the histopathological features between PPEs and other entities presenting with dyskeratosis.

METHODS AND RESULTS

To investigate whether histopathological findings can be used to discriminate among PPEs and other entities presenting with dyskeratotic keratinocytes, cutaneous histopathological changes of PPEs associated with AOSD (n = 26) were compared with those of systemic lupus erythematosus (SLE) (n = 16), dermatomyositis (n = 19), and drug eruption (n = 16). Dyskeratosis was observed in the upper one-third of the epidermal layer in all 26 PPEs. The rate of dyskeratosis for PPEs was higher than that for SLE (18.8%) and dermatomyositis (15.8%). In drug eruptions, the dyskeratotic cells were distributed in all levels of the epidermis. Variable densities of neutrophils were found in the dermis in all PPEs.

CONCLUSIONS

Although this was a retrospective study conducted at a single centre, presentation of dyskeratotic keratinocytes in the upper one-third of the epidermal layer is a distinctive histopathological reactive pattern of PPEs. This pattern may be a useful histopathological marker for early diagnosis of AOSD.

Langerhans Cells Prevent Autoimmunity via Expansion of Keratinocyte Antigen-Specific Regulatory T Cells

Langerhans cells (LCs) are antigen-presenting cells in the epidermis whose roles in antigen-specific immune regulation remain incompletely understood. Desmoglein 3 (Dsg3) is a keratinocyte cell-cell adhesion molecule critical for epidermal integrity and an autoantigen in the autoimmune blistering disease pemphigus. Although antibody-mediated disease mechanisms in pemphigus are extensively characterized, the T cell aspect of this autoimmune disease still remains poorly understood. Herein, we utilized a mouse model of CD4⁺ T cell-mediated autoimmunity against Dsg3 to show that acquisition of Dsg3 and subsequent presentation to T cells by LCs depended on the C-type lectin langerin. The lack of LCs led to enhanced autoimmunity with impaired Dsg3-specific regulatory T cell expansion. LCs expressed the IL-2 receptor complex and the disruption of IL-2 signaling in LCs attenuated LC-mediated regulatory T cell expansion in vitro, demonstrating that direct IL-2 signaling shapes LC function. These data establish that LCs mediate peripheral tolerance against an epidermal autoantigen and point to langerin and IL-2 signaling pathways as attractive targets for achieving tolerogenic responses particularly in autoimmune blistering diseases such as pemphigus.

•

Langerhans cells take up a keratinocyte-expressed autoantigen, desmoglein 3, via langerin.

•

Langerhans cells suppress autoimmunity by expanding regulatory T cells.

•

IL-2 receptor signaling occurs in Langerhans cells, conditioning them to mediate peripheral tolerance.

Lymphocytes are critical for combating pathogens, but they can cause autoimmune diseases when misdirected against autoantigens. While past experimental models have provided detailed mechanisms utilizing neo-antigens, immune regulation against naturally-expressed autoantigen(s) remains largely unexplored. Herein, we studied immune responses against desmoglein 3, a bona fide autoantigen in pemphigus, and demonstrated that epidermal Langerhans cells (antigen-presenting cells) take up the autoantigen from surrounding keratinocytes via a C-type lectin receptor to induce regulatory T cells, which are critical for immune suppression. IL-2 signaling in Langerhans cells was required to preferentially expand regulatory T cells, providing new insights into mechanisms that regulate autoimmunity.